Tutorial

How to Detect Any Website's Tech Stack with a Single API Call

Published March 28, 2026 · 7 min read

Every website leaves fingerprints. The JavaScript framework it runs, the CDN delivering its assets, the analytics tracking its visitors, the payment processor handling its checkout — all of it is detectable from the outside. The question is how to extract that information reliably, at scale, without manual guesswork.

StackPeek's website technology detection API answers that with a single GET request. Send a URL, get back a structured JSON response listing every technology the site uses — in under 500ms.

Why Tech Stack Detection Matters

Knowing what technology a website uses is not just trivia. It is actionable intelligence across multiple domains:

Competitive intelligence

Before choosing your own stack, see what your competitors are running. Are they on Next.js or Nuxt? Using Cloudflare or AWS CloudFront? If three out of five competitors switched to a particular framework, that is a signal worth understanding.

Lead generation and sales intelligence

Sales teams use tech stack data to qualify leads before outreach. If you sell a Shopify integration, you need to know which prospects are actually running Shopify. If you offer a React consulting service, you want to find companies using React. Tech stack detection turns a cold list into a filtered, high-intent pipeline.

Security auditing

Security teams use technology detection to audit exposed dependencies. If a site is running an outdated version of jQuery or exposing its server framework in HTTP headers, those are attack vectors. Automated tech stack scanning across your organization's properties catches these exposures before adversaries do.

How StackPeek's API Works

StackPeek takes a different approach from tools like Wappalyzer or BuiltWith. Instead of launching a headless browser to render the page (slow, expensive, fragile), StackPeek analyzes the raw HTTP response:

This approach means responses come back in under 500ms instead of the 2-8 seconds typical of browser-based scanners. No headless Chrome, no Puppeteer, no rendering costs.

Quick Start: Code Examples

curl

The simplest way to detect a website's tech stack — one line in your terminal:

curl "https://stackpeek.web.app/api/v1/detect?url=https://stripe.com"

Node.js

const response = await fetch(
  "https://stackpeek.web.app/api/v1/detect?url=https://stripe.com"
);
const data = await response.json();

console.log(`Found ${data.technologies.length} technologies:`);
data.technologies.forEach(tech => {
  console.log(`  ${tech.name} (${tech.category}) — ${Math.round(tech.confidence * 100)}%`);
});

Python

import requests

response = requests.get(
    "https://stackpeek.web.app/api/v1/detect",
    params={"url": "https://stripe.com"}
)
data = response.json()

for tech in data["technologies"]:
    print(f"{tech['name']} ({tech['category']}) — {tech['confidence']:.0%}")

What It Detects: 120+ Technologies Across 15 Categories

StackPeek's fingerprint database covers the technologies that matter most for competitive analysis, lead qualification, and security auditing:

Real Example: Scanning stripe.com

Here is what StackPeek returns when you scan stripe.com:

{
  "url": "https://stripe.com",
  "technologies": [
    { "name": "React", "category": "framework", "confidence": 0.94 },
    { "name": "Next.js", "category": "framework", "confidence": 0.91 },
    { "name": "Cloudflare", "category": "cdn", "confidence": 0.97 },
    { "name": "Stripe", "category": "payment", "confidence": 0.99 },
    { "name": "Google Analytics", "category": "analytics", "confidence": 0.96 },
    { "name": "Segment", "category": "tag_manager", "confidence": 0.89 },
    { "name": "Sentry", "category": "monitoring", "confidence": 0.85 }
  ],
  "scanTime": 287
}

Seven technologies identified in 287 milliseconds. Each result includes a confidence score so you can filter out low-certainty matches programmatically.

Use Cases in Practice

Sales teams: qualify leads by tech stack

A sales team selling a Shopify app can pipe their prospect list through StackPeek's API and instantly filter to only companies running Shopify. No more wasted emails to prospects on WooCommerce. Integrate it into your CRM pipeline — scan a lead's domain on import, tag them by tech stack, and route to the right sales sequence automatically.

Security teams: audit dependencies at scale

Run StackPeek against every domain your organization owns. Flag sites still serving jQuery 2.x, sites exposing their server framework in headers, or properties that silently added third-party tracking scripts. Schedule weekly scans to catch drift before your next penetration test does.

Developers: choose compatible tools

Building an integration or plugin? Scan your target customers' websites to understand which frameworks and platforms are most common. If 60% of your users are on Next.js and 30% on Nuxt, you know where to focus your compatibility testing. Real data beats assumptions.

Try the live scanner

Paste any URL and see its full tech stack in seconds. No signup, no API key, completely free.

Scan a website now →

Getting Started

StackPeek's API is designed to be zero-friction:

  1. Free tier: 100 scans per day, no API key required. Just send requests.
  2. Starter plan ($9/mo): 5,000 scans per month with an API key for higher rate limits.
  3. Pro plan ($29/mo): 25,000 scans per month for production workloads and batch scanning.

The API returns standard JSON with consistent field names across all technologies. Every response includes a scanTime field (in milliseconds) and confidence scores between 0 and 1 for each detected technology.

Whether you are building a sales intelligence tool, a security scanner, or just curious about how a website is built — one API call gives you the answer.

Try StackPeek free →